Democratic presidential candidate Martin O'Malley says if he becomes president he will get tough with Wall Street.

The former Maryland governor penned an open letter to megabanks charging that the corporations "pose an enormous risk to the financial system, the economy, and American families." He further outlined what he sees as necessary steps to bring more regulations to large banks and tax high-frequency trading to prevent another economic crash and protect the public in a 10-page policy white paper.

“The high-risk, reckless, and illegal activities of your megabanks were the primary cause of the 2008 crash, which caused the worst recession since The Great Depression, and cost the American economy an estimated $14 trillion to $22 trillion,” Mr. O’Malley wrote in the letter.

Describing the megabanks as “too-big-to-prosecute and too-big-to-jail” he added: “As President, I have no plans to let up on you. I’ll work tirelessly to eliminate the unique danger posed by the handful of too-big-to-fail banks.”

O'Malley said he would seek to reinstate the Glass Steagall Act, the Depression-era measure that separated commercial and investment banking until it was repealed during the Clinton administration in 1999.

The letter has helped bring the long-shot candidate back into the forefront of the presidential campaign, at least momentarily. So far, former Secretary of State Hillary Clinton and Vermont Senator Bernie Sanders have been the dominant voices in the bid for the Democratic nomination. O'Malley lags well behind Mrs. Clinton and Senator Sanders in early nominating state polls and political commentators say the chances that he will gain traction as much as his fellow democrat contenders are low.

O'Malley has long been trying to position himeself to the left of Clinton, but as the Monitor's Linda Feldmann notes, Sanders already fills that role. Ms. Feldmann writes:

First, Clinton is already polling well among liberals, leaving not much room for O’Malley. Add to that the presence of Vermont Sen. Bernie Sanders (I), a self-described socialist, in the race, and O’Malley really gets squeezed.

But there’s another problem: O’Malley is actually less liberal than Clinton. FiveThirtyEight’s system shows him a fair bit to her right, based on fundraising data (i.e., no history of raising money on the left) and public statements. O’Malley is a “moderate liberal” on issues, to Clinton’s “hardcore liberal,” according to the ratings of OnTheIssues.org.

But Feldmann adds that there are few reasons that he should take his chance: He is a first-time candidate and he could benefit from any Clinton fatigue that may emerge, he has a rich record as governor on which to campaign, and he could end up as Clinton’s running mate.